IQueryEngineFilter.AddTypeParser

参数

返回

IQueryEngineFilter The current filter.

描述

Add a type parser specific to the filter.

Add a type parser specific to the filter that parses a string and returns a custom type. Used by custom operator handlers. This type parser will only be used by this filter and will not affect other filters.

// Add a new type parser for Vector2 written as "[x, y]", but only for this filter.
// This type parser will not affect other filters.
queryEngine.TryGetFilter("p", out var filter);
filter.AddTypeParser(s =>
{
    // If the format requirement is not met, return a failure.
    if (!s.StartsWith("[") || !s.EndsWith("]"))
        return ParseResult<Vector2>.none;

    var trimmed = s.Trim('[', ']');
    var vectorTokens = trimmed.Split(',');
    var vectorValues = vectorTokens.Select(token => float.Parse(token, CultureInfo.InvariantCulture.NumberFormat)).ToList();
    if (vectorValues.Count != 2)
        return ParseResult<Vector2>.none;
    var vector = new Vector2(vectorValues[0], vectorValues[1]);

    // When the conversion succeeds, return a success.
    return new ParseResult<Vector2>(true, vector);
});

See IQueryEngineFilter for a complete example.